Post History
#1: Initial revision
Your `a` and `b` are reversed in that equation because that equation corresponds to the tracks `(0..1]` and `[1..)` of [this][0], that are symmetric. The `1 / x` plot is [at least] doubly symmetric. One of those two symmetries is `y = x`. That one's the symmetry axis you are asking about. HTH. [0]: http://en.wikipedia.org/wiki/1/x